Electrically severing stranded wire structure



Dec. 18, G c B V ELECTRICALLY SEVERING STRANDED WfRE STRUCTURE Filed Oct. 20, 1931 2 Sheets-Sheet l A TTORNEY Patented Dec. 18, 1934 nmcrnromr SEVERING STRANDED W13 1 STRUCTURE Gorman 0. Hard, Adrian, Mich., assignor to American Cable Company, Inc., New York,

N. Y., a corporation of Delaware Application October 20,

8 Claims.

This invention relates to machines for severing, by means of an electrical current, such articles as wire rope or other stranded wire structures; also wires, wire rods, and in general any metal articles which may be so severed.

An object of the invention is to provide a novel method by which articles of the above description may be severed accurately and rapidly, with a minimum expenditure of labor and with only the degree of skill which may be commonly expected of unskilled workmen or workmen of average mechanical training.

A more particular object of the invention is to provide a method of severing wire rope or similar stranded wire structures in such a manner that the severed ends of the component wires will be compactly united metallically to constitute a terminal portion somewhat reduced in cross sectional area from the diameter of the body portion of the wire rope, so that this end portion may be readily inserted into sockets of a diameter corresponding to, or closely approximating that of, the rope diameter, without the necessity for grinding or otherwise finishing the terminal portion to be so fitted into the attachment.

In existing methods of cutting wire rope, etc. electrically, there has been experienced a tendency of the metal melted or softened by the heating effect of the cutting current to gather and swell between the component wires adjacent to their severed portions sothat a ball of metal is formed which swells to a diameter sufficiently larger than that of the rope diameter to form an enlargement which will not pass into a socket of proper diameter to fit the rope which is to be attached, but must be reduced by grinding or otherwise before the rope and fitting can be connected.

This operation involves considerable loss of time, labor and material and interferes seriously with the successful employment of electrical cutting as a means for severing stranded wire and similar structures.

Another object of the invention is to provide a machine adapted to carry into effect the method briefly described above and which will be described inore atlength hereinafter.

The above and other features of the invention are illustrated and described fully in the accompanying drawings and specification and are pointed out in the claims.

In the drawings- Fig. 1 is a view in front elevation of a machine in the construction of which the invention 1931, Serial No. 569,935

has been embodied and which is adapted to carry into effect the method of the present invention.

Fig. 2 is a plan view of the same.

Fig. 3 is a fragmentary detail view in side ele- 5 vation of a portion of the machine.

Fig. 4 is a fragmentary detail view in vertical longitudinal section taken on the line 4-4 of Fig. 2, upon a larger scale, parts being broken away.

Fig. 5 is a fragmentary detail view, on a still larger scale, of the ends of a wire rope, after severance.

The novel method of the present invention comprises the step of passing an electrical current through the wire cable, wire or other article to be severed, of sufficient volume to cause an initial heating and softening effect, while at the same time the cable is subjected to a tension suiiicient to stretch the cable to a predeterminedextent at a region localized at the point where. severance is to be effected; then the part so stretched is held without tension and an electrical current is passed therethrough of suflicient volume to fuse the cable at the region to be severed and thereby sever the same.

As a result of the above-described operation, each of the severed ends produced is found to present a compactterminal portion of solid metal formed by agglomerated fused portions of the component wires, which are thus metalli-' cally united or welded together, each terminal portion thus formed tapering somewhat toward the end so that the diameter at the end is sufiiciently less than that of the average diameter of the cable or rope to facilitate easy fitting of the end into a socket or in any aperture of a diameter corresponding closely to that of the rope diameter.

By reason of the fact that no tension is exert- 40 ed on the rope during the step of passing the severing current, each of the severed ends is not pointed sharplybut has a diameter which may approach that of the rope diameter as closely as may be desirable, the diameter of the severed portion being controllable more or less by the degree to which the rope has been stretched during the operation of preliminary heating and stretching constituting the first step of the method above described.

In a now preferred embodiment of a machine adapted to carry the abovedescribed method into efiect, the part designated by the reference character 11 isthe base of the machine which may be of any suitable character and contain such operating instrumentalities as transformers, switches and other apparatus incidental to the structure of this type of machine which may, in general, correspond to machines of this type in conventional use and need not be described in detail.

Upon the top 12 of this base are mounted two clamping heads 13 ,and 14, of which that shown at the lefthand side of Fig. 1 is mountedin fixed position upon the table top, this head being shown in elevation in Fig; 3.

In the form selected for illustration, it comprises a plurality of uprights '15; preferably formed integrally with the table, and between which is mounted a jaw 16 pivoted at17 in a bracket 18 extending upwardly from the sup Above the clamping jaw'is mounted a cammember 23 upon a short shaft 24 around which the cam may-be oscillated bymeans of a hand lever 25, the cam engaging with the upper surface of the clamping jaw which is preferably provided with an adjustable wedge-shaped plate 26, to permit adjustment for operation upon cables of difierent diameters.

The other clamping head 14 is composed of parts'similar in all respects to those just described with reference to the clamping head 13 and whichbear the same {reference characters and will not be again described in detail.

Theclamping head 14 is, however, so mounted upon thetable top that it can be moved along the axis'of the wire rope or other article to be severed, for which purpose the clamping head has an extended slide member 2'7 working on suitable guides 28 upon the table top. Its range of movement is preferably limited by a suitable adjustable stop taking the form of a threaded post 29 fixed in the slide, and passing through an apertured bracket 30 extending upwardly from the supporting structure of the base 11, the post 29 being provided with nuts 31, 32, which may be set for engagement with the bracket 30 at the desired limits.

The slide may be moved by any suitable mechanism, and for this purpose the drawing shows a lever 35 fixed on a rock-shaft 33 mounted to oscillate in the bracket 30 and in a bracket 34 extending from the base 11, the lever 35 having its free end connected to the slide 27 of themovable clamping head 14 (see Fig. 3) by means of a toggle-link 36 comprising eye bolts 37 and 38 joined by a turn-buckle 39 by means of which the link may be shortened or lengthened so that a given angular movement of the lever 35 will result in a longer or shorter throw of the slide 27 and movable clamping head 14.

' Upon the shaft 33 is mounted a lever 40 from the outer end 41 of which is suspended plvotally a weight 42 by means of a rod 43. The lower end of the rod is preferably connected to a treadle 50 mounted pivotally upon a fulcrum bracket 51 supported on the floor or on any other suitable support, the lever having a pedal 52' by means of which the operator may raise the weight and cause upward movement of the arm 40 of the lever from which the weight is suspended, thereby causing the slide 27 and movable clamping head 14 to approach the fixed clamping head in the manner already described, until stopped by the nuts 32, as in Fig. 2.

The lever 40 is also provided with means adapted to control the turning on and off of the a set screw'fiadapted to be engaged with a lever 55' mounted pivotallyat 56 upon the outer wall of the base 11, the free end of the lever 55 extending across a plunger 57 which constitutes the controlling means for an electrical switch preferably contained within the base 11 and which may be of any form suitable to cause the current to'be turned on and off at will when operated by the lever 55, the formmof switch being immaterial and sonot requiring description, as anysuitable' conventional form may be used for the purpose 1 For the purposeof the :presentdescription it is sufilcie'nt to' understand that when the foot pedal 52 is released, the weight 42 causes down ward movement of thearm 40 and upward releasing the lever 55and the switch plunger 57, whereupon the'switch closes connections suitable to cause passage of current/When the treadle 52 is depressed and the weight is raised the lever'controlling the-"switch plunger 57 is forced downwardly by the screw 54 and the current is cut off.

In the operation of the machine above described the end of a wire cable or other article to be severed, or an end of each of several cables, indicated by the reference character R, and which may be derived from any suitable stock supply, is led between the clamping jaws and extended along the machine until it is of the desired length to be severed. It may beadvantageously engaged with a stop 58 mounted upon an extension 59 of the bracket 34 carried by the machine base 11.

The handle 25 of the fixed clamping head 13 is then raised into the position shown in Figs. 1, 2 and 3 which results in firmly clamping the cable in the fixed clamping head.

The movable clamping head 14 is then moved,

while still open, into the position shown in Fig.

1, which may be eifected by pressing down upon the foot pedal 52, thus raising the weight 42 and straightening the toggle-link 36, so that the slide 27 and'its clamping head 14 are moved toward the fixed clamping head into the position shown in Fig. 1, and then the handle 25 of the movable clamping head is raised and the clamping jaws are secured upon the cable or other article to be severed, the cable thus being clamped at a distance from the fixed clamping head suitable to leave between the clamping heads a portion of stock 1- which can be stretched to proper length to permit the desired severing action of the current.

This length of the portion 1' will, of course,

vary according to the nature of the stock undertreatment and the character of severed ends which it is desired to produce. In the instance shown,a portion of stock 1' of about one quarter '30 movement of the arm 53 and the'set screw 54,

of an inch in length is left between the clamping heads.

It is also to be understood that these clamping heads are suitably insulated. from each other, and suitably connected to the source of electrical current. such connections not requiring-description nor special illustration as they are well known in the art, this portion of the apparatus being of conventional construction in'the instance illustrated. I

pursuance of. the method of the present invention, when the cable stock is being clamped innplace, as just described, by the operation of depressing the'treadle,-this operation causes the electrical switch to. be held open as already indicated so that no current is. passing while the .to become melted.

As this section between the electrodes becomes hot and soft, the tension exerted by the weight 42 rocks the shaft 33, breaks the toggle 36, and the ensuing movement of the slide 27 and clamping head 14 stretches the cable. The slide moves tothe right until the stop nuts 31 reach the fixed bracket and after this point is reached there is no tension on the cable, the tension or load being carried or-held by the stop nuts against the fixed bracket.

All this is done before the cable has had time At this step of the method the section of cable between the heads presents the appearance shown in Fig. 4 of the drawings. That is to say, its diameter is reduced preceptibly from the original rope diameter and is .joined with the rope portions on each side by conical tapering regions as indicated.

The next step in carrying the method into effect is to apply a melting current sufiicient to cause severance electrically of the cable by melting the same at the region of reduced diameter.

As soon as this portion of the cable reaches the melting point, a few sparks fly and the cable is severed, a space of about one-sixty fourth of an inch being left between the two ends.

These ends now present the appearance shown in Fig. 5 which is shown upon an enlarged scale and from which it will be seen that each end has a terminal portion composed of the solidifled metal which has been fused from the component strand wires and which extend approximately at right angles to the longitudinal axis of the cable, tapering gradually to the body diameter of the cable.

Such a terminal may be readily introduced into any socket or aperture of a fitting with which it is desired to connect this end of the cable. This terminal may have a small crater or be slightly concave without interference with its usefulness.

The operation of the novel method disclosed thus results in the formation of a cable section which, in the instance illustrated, is marked R and which has at each end a terminal of the character shown in Fig. 5, it being understood that the operation above described may be repeated as long as the stock holds out, each severed portion of stock B being finished at each end in the manner described. I

It is tobe noted that there is absolutely no tension on the cable at the time the cable .becomes moltenduring the severing operation and it is found in practice thatby the preliminary heating and stretching operation under tension, followed by the passage of a severing currentwhile the cable is not under tension, the desired result is achieved of producinga clean solid cable terminal, tapering suiiicientlyforthe desired purpose of introducing the; same to thesocket of a fitting with which it is to be connected, it being understood that this is but one applied use of the product, which is susceptible of many advantageous uses other than that .just described.

I claim: a

1. The method of severing an article of the class described which comprises the steps of holding a restricted portion of said article under tension and passing through said restricted portion an electrical heating current until said portion is softened, stretching said soft portion until it is reduced in diameter locally, then passing a melting current through the said localized region of reduced diameter while holdingsaid portion free from tension until said articleis severed at that region.

2. The method of severing a stranded wire structure of the class described which comprises the steps of holding a restricted portion of said article under tension and passing through said restricted portion an electrical heating current.

until said portion is softened, stretching said soft portion until it is reduced in diameter locally, then passing a meltingcurrentthrough the said localized region of reduced diameter while holdingv said portion free from tension until said article is severed at that region, said method resulting in the formation of a terminal on each side of the region ofseverance, each such terminal having its component wires connected by a mass of fused metal smaller in diameter than that of the cable stock and connected with the body portion of the cable by a portion tapering toward the end.

3. The method ofsevering a stranded wire the said localized region of reduced diameter while holding said portion free from tension until said article is severed at that region, said method resulting in the formation of a terminal on each side of the region of severance, each such terminal having its component wires connected by a mass of fused metal smaller in diameter than that of the cable stock and connected with the body portion of the cable by a portion tapering toward the end, said end being of substantial area and substantially at right angles to the longitudinal axis of the cable.

4. In a machine for electrically severing stranded wire articles such as cable, rope or strand, clamping devices adapted to engage the article to be severed at selected regions spaced on each side or the region of severance, and means to supply electric current to the portion of said article between said clamping devices; means to cause relative movement between said clamping devices thereby to apply tension to the portion of said article therebetween; means to control the flow of electrical current to said article, whereby current may be caused to flow to said portion to initially heat and soften the same and thereby to facilitate elongation thereof under said tension and reduction in its diameter, and to subsequently melt and sever said portion; and means for limiting said relativemovement of the clamp devices .whereby said portion will be held free of tension while it is being severed.

5. In a machine for electrically severing stranded wire articles such as cable, rope or strand, clamping devices adapted to engage the article to be severed at selected regions spaced on each side of the region of severance, and means to supply electric current to the portion of said article between said clamping devices; one of said clamping devices being movable in the direction of the axis of the rope; means adapted to urge said movable clamping device away from said other clamping device, thereby to apply tension to the portion of said article between said clamping devices, means to control the flow of electrical current to said article, means to limit the extent of tension applied to said article, and connections between said tensioning devices and said current controlling devices, whereby current is caused to flow to said portion to be severed, to heat and thus to soften the same and facilitate elongation thereof by the application of tension thereto and thereby to cause reduction in its diameter untilthe predetermined range of separation of said clamping heads is reached; said means being adapted also to cause flow to said elongated and constricted portion of current suflicient to melt and sever said portion while it is held without tension, said connections also serving to cause approach of said clamping devices toward each other at times against the urge of said clamp-separating means, and at the same time to cut oflf the flow of current.

6. In a machine for electrically severing stranded wire articles such as cable, rope or strand, clamping devices adapted to engage the article to be severed at selected regions spaced on each side of the region of severance, and means to supply electric current to the portion of said article between said clamping devices; one of said clamping devices being movable in the direction of the axis of the rope; means tending constantly to urge said movable clamping device away from said other clamping device, thereby to apply tension to the portion of said article between said clamping devices, means to control the flow of electrical current to said article, means to limit the extent of tension applied to said article, and manually operated connections between said tensioning devices and said current controlling devices, whereby current is caused to flow to said portion to be severed, to heat and thus to soften the same and facilitate elongation thereof by the application of tension thereto and thereby to cause reduction in its diameter until the predetermined range of separation of said clamping heads is reached; said means being adapted also to cause flow to said elongated and constricted portion of current suflicient to melt and sever said portion, while it is held without tension,

said connections also serving when operated manually in reverse direction to cause approach 7 of said clamping devices toward each other at times against the urge of said clamp-separating means, and at the same time to cut oil the flow of current.

7. The method of severing an article of the class described, which comprises the steps of heating to plasticity a definite short length of the same, at the same time stretching the said definite short length as it assumes a state of plasticity .to an extent short of pulling it apart, then, without further elongation of the said length, applying to it sufficient heat to fuse it in the region of its smallest diameter.

8. The method of severing an article of the class described, which comprises the steps of.

passing an electric current through a definite short lengh of the same, at the same time stretching the said length as it softens under the influence of the current to an extent short of pulling it apart, then, without further elongation of the said length, passing through it a current suflicient to fuse it in the region of its smallest diameter.

' GORMAN C. BURD. 

